feat: dashboard-only mode and keystone settings integration

The second display is now optional: [display] enabled = false skips the
headless output, wayvnc, AVNC and the VNC tunnel, so the tablet runs the
dashboard alone. `deck-it env` reports it as EXTEND.

Keystone's new deck-it page (quickshell, desktop/modules/deckit) edits
the config and the autostart line, which needed:

- The user config is merged over the shipped config.toml key by key
  within each table instead of replacing it whole, so the page writes a
  sparse file and an unset key falls back to the default.
- `deck-it defaults` prints the shipped config as JSON for the page's
  placeholders, so keystone never copies the defaults.
- `deck-it status` prints one JSON line (server, display, waiting,
  tablet, extend) for the page's status line and restart check.
- [launch] is now `apps`, a list of desktop ids run with gtk-launch,
  with name and icon read from the .desktop file, so the page can pick
  launchers from the installed apps. The old command tables are gone;
  the client still sends only an id, which must be listed and installed.
  A launcher whose icon the theme lacks shows its name.
- [wifi] address gives the tablet's address in config. The last address
  that worked is kept in ~/.config/deck-it/last-wifi: `stop` deletes the
  runtime serial file, so a restart from the page used to wait forever.
- `stop` also ends a login's `wifi --wait`, matched by its own command
  line only, so repeated restarts do not pile up waiters.

Also fixed: `deck-it env` fell through into the usage text, and the
usage text printed the license header since the header was added.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

3 files changed, 77 insertions, 44 deletions

diff --git a/deckit/__main__.py b/deckit/__main__.py
index 5b6cda8..98a7169 100644
--- a/deckit/__main__.py
+++ b/deckit/__main__.py
@@ -14,7 +14,7 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-"""`python3 -m deckit [setup-display | env]`."""
+"""`python3 -m deckit [setup-display | env | defaults]`."""
 
 import sys
 
@@ -27,7 +27,12 @@ def main():
         cfg = config.load_config()
         d, p = cfg.get("display", {}), cfg.get("ports", {})
         print(f"MON={d.get('name', 'TAB')} PORT={p.get('command_center', 8765)} "
-              f"VNC_PORT={p.get('display', 5900)}")
+              f"VNC_PORT={p.get('display', 5900)} EXTEND={int(d.get('enabled', True))} "
+              f"WIFI_ADDR={cfg.get('wifi', {}).get('address', '')}")
+    elif args == ["defaults"]:
+        # For keystone's settings page: the shipped values a user file overrides.
+        import json
+        print(json.dumps(config.defaults()))
     elif args == ["setup-display"]:
         from .display import setup_display
         setup_display(config.load_config())
diff --git a/deckit/config.py b/deckit/config.py
index aac5ad9..e20bc00 100644
--- a/deckit/config.py
+++ b/deckit/config.py
@@ -24,6 +24,8 @@ from pathlib import Path
 
 ROOT = Path(__file__).resolve().parent.parent
 MONITOR_NAME = re.compile(r"[A-Za-z0-9_-]{1,32}")
+WIFI_ADDR = re.compile(r"[A-Za-z0-9.-]{1,253}:[0-9]{1,5}")
+DESKTOP_ID = re.compile(r"[A-Za-z0-9._-]{1,255}")
 
 
 def user_config_path() -> Path:
@@ -34,6 +36,8 @@ def config_error(cfg: dict) -> str | None:
     d, ports = cfg.get("display", {}), cfg.get("ports", {})
     if not MONITOR_NAME.fullmatch(str(d.get("name", "TAB"))):
         return "display.name must be letters, digits, - or _"
+    if not isinstance(d.get("enabled", True), bool):
+        return "display.enabled must be true or false"
     refresh = d.get("refresh", 60)
     if not isinstance(refresh, int) or not 1 <= refresh <= 240:
         return "display.refresh must be a number from 1 to 240"
@@ -44,13 +48,35 @@ def config_error(cfg: dict) -> str | None:
                 return f"ports.{key} must be a number from 1024 to 65535"
     if ports.get("command_center", 8765) == ports.get("display", 5900):
         return "ports.command_center and ports.display must differ"
+    addr = cfg.get("wifi", {}).get("address", "")
+    if addr and not (isinstance(addr, str) and WIFI_ADDR.fullmatch(addr)):
+        return "wifi.address must be host:port, like 192.0.2.10:37099"
+    apps = cfg.get("launch", {}).get("apps", [])
+    if not isinstance(apps, list) or not all(isinstance(a, str) and DESKTOP_ID.fullmatch(a) for a in apps):
+        return "launch.apps must be a list of desktop ids, like \"kitty\""
     return None
 
 
+def merge(base: dict, over: dict) -> dict:
+    """The user's file over the defaults, key by key within each table."""
+    out = dict(base)
+    for key, value in over.items():
+        both = isinstance(value, dict) and isinstance(base.get(key), dict)
+        out[key] = {**base[key], **value} if both else value
+    return out
+
+
+def defaults() -> dict:
+    with open(ROOT / "config.toml", "rb") as f:
+        return tomllib.load(f)
+
+
 def load_config() -> dict:
-    path = user_config_path() if user_config_path().is_file() else ROOT / "config.toml"
-    with open(path, "rb") as f:
-        cfg = tomllib.load(f)
+    cfg, path = defaults(), ROOT / "config.toml"
+    if user_config_path().is_file():
+        path = user_config_path()
+        with open(path, "rb") as f:
+            cfg = merge(cfg, tomllib.load(f))
     if err := config_error(cfg):
         sys.exit(f"{path}: {err}")
     return cfg
diff --git a/deckit/modules/windows.py b/deckit/modules/windows.py
index 5457b16..1907b59 100644
--- a/deckit/modules/windows.py
+++ b/deckit/modules/windows.py
@@ -14,7 +14,7 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-"""Hyprland windows, workspaces, and launching config-declared commands."""
+"""Hyprland windows, workspaces, and launching config-listed apps."""
 
 import json
 import re
@@ -24,7 +24,8 @@ from pathlib import Path
 from ..module import Module, ModuleError
 
 ADDR = re.compile(r"0x[0-9a-f]{1,16}")
-DESKTOP_BASES = (Path("/usr/share/applications"), Path.home() / ".local/share/applications")
+# The user's own entries first, so they win over the system's, as in a launcher.
+DESKTOP_BASES = (Path.home() / ".local/share/applications", Path("/usr/share/applications"))
 
 
 def _run(cmd, timeout=2):
@@ -46,40 +47,47 @@ def _dispatch(cmd):
         pass
 
 
-def _desktop_icons(bases=DESKTOP_BASES) -> dict:
-    """Window class -> candidate icon names, from the installed .desktop files."""
-    mapping = {}
+def _desktop_entries(bases=DESKTOP_BASES) -> dict:
+    """Desktop id -> {name, icon, wmclass}, from each [Desktop Entry] section."""
+    entries = {}
     for base in bases:
         if not base.is_dir():
             continue
         for entry in base.glob("*.desktop"):
+            if entry.stem in entries:
+                continue
             try:
                 text = entry.read_text(errors="replace")
             except OSError:
                 continue
-            section = None
-            icon = wmclass = None
+            found, inside = {}, False
             for line in text.splitlines():
                 line = line.strip()
-                if line.startswith("[") and line.endswith("]"):
-                    section = line
-                    if section != "[Desktop Entry]":
+                if line.startswith("["):
+                    if inside:
                         break
-                    continue
-                if section != "[Desktop Entry]":
-                    continue
-                if line.startswith("Icon="):
-                    icon = line.split("=", 1)[1].strip()
-                elif line.startswith("StartupWMClass="):
-                    wmclass = line.split("=", 1)[1].strip()
-            if not icon:
-                continue
-            candidates = [icon]
-            if wmclass and wmclass != icon:
-                candidates.append(wmclass)
-            for key in (entry.stem, wmclass):
-                if key:
-                    mapping.setdefault(key.lower(), candidates)
+                    inside = line == "[Desktop Entry]"
+                elif inside and "=" in line:
+                    key, value = line.split("=", 1)
+                    if key in ("Name", "Icon", "StartupWMClass"):
+                        found.setdefault(key, value.strip())
+            entries[entry.stem] = {"name": found.get("Name"), "icon": found.get("Icon"),
+                                   "wmclass": found.get("StartupWMClass")}
+    return entries
+
+
+def _desktop_icons(entries: dict) -> dict:
+    """Window class -> candidate icon names, by desktop id and StartupWMClass."""
+    mapping = {}
+    for stem, e in entries.items():
+        if not e["icon"]:
+            continue
+        candidates = [e["icon"]]
+        if e["wmclass"] and e["wmclass"] != e["icon"]:
+            candidates.append(e["wmclass"])
+        for key in (stem, e["wmclass"]):
+            if key:
+                mapping.setdefault(key.lower(), candidates)
     return mapping
 
 
@@ -124,14 +132,10 @@ def _state(run):
 def make(cfg: dict) -> Module:
     run = cfg.get("run", _run)
     lua = hypr_lua(cfg)
-    launch = cfg.get("launch", {})
+    apps = [str(a) for a in cfg.get("launch", {}).get("apps", [])]
     workspaces = cfg.get("windows", {}).get("workspaces", list(range(1, 11)))
-    icons = _desktop_icons()
-
-    def launch_spec(spec):
-        if isinstance(spec, dict):
-            return spec.get("command"), spec.get("icon"), spec.get("label")
-        return spec, None, None
+    entries = _desktop_entries()
+    icons = _desktop_icons(entries)
 
     def workspace(body):
         n = body.get("n")
@@ -164,21 +168,19 @@ def make(cfg: dict) -> Module:
             _dispatch(["hyprctl", "dispatch", "movetoworkspacesilent", f"{n},address:{addr}"])
 
     def launch_key(body):
+        # Only a configured, installed desktop id; gtk-launch runs its Exec.
         key = str(body.get("key", ""))
-        command, _, _ = launch_spec(launch.get(key))
-        if command is None:
+        if key not in apps or key not in entries:
             raise ModuleError("unknown launch key")
-        _popen(["sh", "-c", command] if isinstance(command, str) else command)
+        _popen(["gtk-launch", key])
 
     def state():
         st = _state(run)
         for win in st["windows"]:
             win["icons"] = icons.get(win["class"].lower(), [win["class"].lower()])
         known = sorted(set(int(n) for n in workspaces) | set(st["workspaces"]))
-        launches = []
-        for key, spec in launch.items():
-            _, icon, label = launch_spec(spec)
-            launches.append({"key": key, "icon": icon, "label": label or key})
+        launches = [{"key": a, "icon": entries[a]["icon"], "label": entries[a]["name"] or a}
+                    for a in apps if a in entries]
         return {**st, "workspaces": known, "launches": launches}
 
     return Module(name="windows", title="Windows", state=state,